1. Field of the Invention
This invention relates to a power quality monitoring, detecting and analyzation device. More particularly, it relates to a modular device adaptable to an electrical circuit, utilizing power quality equipment, which permits event counts of various changing electrical phenomenon to be stored in memory and broadcast over a control network.
2. Description of Prior Art
The issue of power quality has always been a concern for people utilizing electronic devices and machinery. Recently, for system engineers of facilities of all sizes, power quality has become their greatest concern. Advances in microelectronics has caused the advent of microprocessor-based equipment to be standard in almost all electronic devices, especially those found in large scale manufacturing and fabrication environments. Although microprocessor devices have resulted in xe2x80x9csmarterxe2x80x9d and more efficient electronic systems and devices, facility and system engineers are quickly discovering that transient voltages and power variations, which previously went unnoticed and were generally of no concern, are now compromising the reliability of the new microprocessor-based devices. One reason microprocessors are so sensitive is that most integrated circuits of today are far more dense and operate at higher speeds than those of even a few years ago and therefore more susceptible to the slightest of electrical anomalies. Where slower speed processors simply ignored the transients, high-speed processors interpret the transient as a command sequence directed at the processor.
Several factors contribute to voltage transients and power variations which degrade the overall power quality of a facility or system. These factors include: installation of highly sensitive electronic equipment and systems in antiquated facilities, use of a new facility that has not been designed with proper power quality in mind, improper or nonexistent power protection plans and improper design and installation of electrical distribution and grounding systems. All of these factors can contribute to poor power quality from resulting transient voltage surges, voltage sags and swells, phase outages, power factor irregularities, increased harmonic distortion and undesired current draw.
The anomalies that contribute to power quality degradation can be initiated by either external or internal causes. External causes such as lightning strikes and utility company faults can be devastating to a facility. But, it has been suggested that only about 20-35% of the power anomalies occur outside the facility, where as much as 65-80% of all power problems can be directly attributed to the local environment. Examples of internal or local environment causes include the use of elevators, air conditioners, vending machines, copiers and large computers. Even the simple task of turning lights on and off can cause rushes of power and transient voltages to travel on the power transmission lines, potentially damaging the circuitry of electronic equipment coupled thereto. For these reasons, systems and devices that suppress, filter and/or eliminate all types of undesired electrical anomalies have become quite common in all types of facilities, businesses and even homes.
There are many types of circuits and equipment that are potentially useful in eliminating undesired electrical anomalies. These power quality equipment (PQE) items include: isolation transformers, uninterruptible power supplies (UPS), voltage regulators, line or power conditioners, designated power distribution chassis, and transient voltage surge suppressors (TVSS), also known as surge protective devices (SPD). Although all of the aforementioned devices have special uses which may dictate their employment in a particular environment, SPD devices are the most widely used and accepted devices for dealing with voltage transients.
Transients are over-voltages or over-currents, typically lasting microseconds, that are caused by external and internal events. Transient voltage surges comprise the most severe and immediate danger to sensitive microprocessor controlled electrical and electronic equipment. For this reason, SPD devices are needed in sensitive electronic facility environments. Without SPD devices, manufacturing facilities utilizing sensitive electrical equipment, for instance robotic assembly, could be devastated if merely one robotic assembler was removed from the assembly line. The costs associated with a shutdown for repairs, replacement and reprogramming of a robotic machine could mean the difference between a profitable and non-profitable year for a company.
Most SPD devices comprise a stand alone unit which are coupled between the power source of a facility and a piece of electronic equipment. Many SPD devices use a combination of MOVs (metal oxide varistors) for high-energy surges and capacitors for low to medium surges and are activated by rise in the line voltage.
Although systems connected to an SPD or other PQE device are said to be adequately protected from transient voltage surges and other power quality anomalies, respectively, deficiencies exist which necessitate improvement thereupon. Specifically, nowhere in the prior art is there a device for monitoring and transmitting electrical phenomenon data adaptable to a SPD/PQE control network. A device is needed which can monitor and/or count the following: SPD/PQE status, voltage levels, current draw, power surges, phase outages, phase shifting, power factor, harmonic distortion and panel load. Such a device needs to be adaptable to a SPD or PQE control network.
The present invention addresses and overcomes the deficiencies in the prior art relating to the monitoring of electrical phenomenon in a control network utilizing TVSS devices. A control network comprises a group of nodes (each having one or more sensors or actuators, plus localized computational capability) which communicate over a type of media using a standard protocol to implement a sense, monitoring or sense and control application. The control network could have two to 20,000 (or more) nodes and can implement simple systems such as a few light switches or highly complex systems such as large robotic assembly lines.
Communication among the nodes may be peer-to-peer (distributed control) or master-slave (centralized control).
One existing protocol for a control network is the LONWORKS protocol developed by Echelon. In a LONWORKS network, a peer-to-peer or master-slave architecture can be used. If a peer-to-peer architecture is employed, no central control is needed. A control network utilizing the LONWORKS protocol can perform a complex control application, such as running a robotic assembly line or automating an entire office building. Yet, each node in the LONWORKS network is capable of performing simple tasks, such as running sensors or motion detectors or actuating switches, relays or motor drives.
The present invention comprises a modular device connectable to a SPD, other PQE device or power panel. The modular device is in turn is coupled to a power source for establishing a power quality control network. In the preferred embodiment, the control network utilizes the LONWORKS protocol.
The modular device couples to a circuit for transient voltage surge suppression. The modular device comprises, a microprocessor neuron chip, surge detection circuitry, isolation circuitry for the transient voltage surge suppression circuitry, a pair of user interface push buttons, a transceiver communication circuit, a power supply, isolation circuitry for the power supply, an LED phase loss indicator, an audible alarm, dry relay contacts, an LCD display, electrical anomaly counting means and drivers for the audible alarm, dry relay contacts, LCD display and LED phase loss indicator. The device further comprises EPROM and programmable array logic coupled to the neuron chip.
The modular device is capable of determining various electrical phenomenon occurring in the electrical line to which the device is coupled, counting the number occurrences of such phenomenon, and transmitting that information to a central location for analysis by a system engineer or administrator of the facility. The central location could be a location within the facility and/or an off-site monitoring station. The detectable electrical phenomenon includes SPD/PQE status, voltage levels, current draw, power surges, phase outages, phase shifting, power factor, harmonic distortion and panel load. Voltage and current detection values may be set to specific levels of monitoring based on user specifications or standards tolerances, for example, voltage and current tolerances defined in Mil Spec 1399.
Different means of communication can be chosen by removing and replacing a separate modular printed circuit board connectable to the modular device. For example, the device can utilize the AC power line as a means for communication by connecting a power line transceiver board. Alternate means of communication include a free topologyxe2x80x94twisted pair connection or RS485, fiber optic, RF carrier and modem communication.
THE LCD display operates in two primary display modes showing surge and phase outage data. The two modes can be toggled therebetween through the use of one of the user interface buttons or by means of transmitted computer command. Various sub-menus are accessible through the actuation of the user interface buttons and include System Control, a Test Mode, a Network Test Mode and Network Setup. The functions carried out in the sub-menus permit a user of the power quality modular device to set-up each device to particular parameters. Such parameters will be discussed in the Detailed Description of the Preferred Embodiment.